There is a nice script you can use, called "RotateTowardPoint".
You would place a path in the center (where you want them all rotated towards).
Then select all and run the script. (I ran it a few times for better results)
Check out this answer for the script and more info.
You'll notice it doesn't do a perfect job, I assume that's a limitation of the computer trying to guess which way you want them all pointing.